Railway signaling



R. R. KEMMERER 2,062,055

RAILWAY SIGNALING Filed March 6, 1936 6 Sheets-Shea*I l Nov. 24, 1936.

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YINVENTOR Ralph Rlemmemf' BY 5 [ILSl ATTORNEY NNN lwll Nov. 24, 1936. R. R. KEMMr-:RER 2,052,055

RAILWAY SIGNALNG Filed March e, 19:56 e sheets-sheet e Patented Nov. 24, 1936 UNETED STATES PATENT OFFICE RAILWAY SIGNALING Application March 6, 1936, Serial No. 67,495

33 Claims.

My invention relates to railway signaling, and particularly to signaling involving wayside signals located along a trackway for governing the passage of trains.

A feature of my invention is the provision of novel and improved apparatus for establishing a distinctive control for each of four sections in the rear of an occupied section. Each distinctive control is eiective to cause a corresponding aspect of the associated wayside signal whereby there is produced a four-block, live-indication, system of signaling.

Another feature of my invention is the provision of novel and improved apparatus for establishing a distinctive control for each' of three sections in the rear of an occupied section for controlling the associated wayside signal whereby there is produced a three-block, four-indication, system of signaling.

I will describe several forms of apparatus each embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Figs. 1A, 1B, and 1C are diagrammatic views which, when placed end to end in the order named, illustrate one form of apparatus embodying my invention for providing four-block, five-indication, signaling. Figs. 2A and 2B are diagrammatic views which, when placed end to end in the order named, illustrate another form of apparatus embodying my invention for providing three-block, four-indication signaling. Figs. 3, 4, and 5 are diagrammatic views each illustrating a modification of a portion of the apparatus shown in Fig. 2A and each also embodying my invention.

Similar reference characters refer to similar parts in each of the several Views.

Referring rst to Figs. 1A, 1B, and 1C, the reference characters Il and I8 designate the rails 4 of a stretch of railway track along which traflic normally moves in the direction indicated by the arrows. These rails are divided by insulated joints I9 into a plurality of track sections or blocks V-W, W-X, X-Y, and Y-Z. 45 As here shown, each track section is divided by insulated joints into at least two subsections IT, 2T, 3T, 4T, etc, Each subsection is provided with a track circuit which includes a track battery 2B connected across the rails at one end of the subsection and a track relay, designated by the reference character TR with a prefix the same as the numerical preX in the reference character for the associated subsection, connected across the rails at the other end of the subsection.

To govern the passage of trains through the stretch, a wayside signal designated by a suitable distinguishing reference character is located at the entrance to each track section. Each of these signals includes an upper unit U and a lower unit L. These units may take any one of several forms of signal mechanism such as searchlight, semaphore, color light, or position light. As here shown, each unit U and each unit L is a searchlight signal mechanism substantially as described and claimed in United States Letters Patent No. 1,864,224, granted June 21, 1932, to W. B. Wells, for Light signals.

For the purpose of this application, it is deemed suicient to describe but briefly these signals. The upper unit U of signal Ill, for example, includes a pivotally mounted rotor 2l controlled by a permanent magnet (not shown) and by an operating winding 22. Energization of operating winding 22 by current of one polarity causes rotor 2| to be rotated in one direction, moving the signal to the clear indication position; energization of operating winding 22 by current of the opposite polarity causes rotor 2| to be rotated in the opposite direction to move the signal to the caution indication position; while deenergization of operating winding 22 permits rotor 2| to be returned by gravity to an interi mediate position, which is the stop indication position.

Associated with rotor 2l is a lamp IOUE. As pointed out in detail in the aforementioned patent, when rotor 2| is rotated to the clear position, a green colored iilter G is moved in front of lamp IIJUE so that a green signal light will be displayed when the lamp is lighted. When rotor 2l is rotated to the caution indication position, a yellow colored i'llter Y is moved in front of lamp IUUE so that a-yellow signal light is displayed when the lamp is lighted. In a like manner, the positioning of rotor 2l in the intermediate position moves a red colored filter R in front of lamp IUUE so that a red signal light is displayed whenever the lamp is lighted.

Each of the searchlight mechanisms U and L with their associated lamps UE and LE, for each of the signals, functions in a manner similar to that just described for the mechanism U and lamp UE of signal l0.

Each section is provided with a line circuit including a pair of line wires each of which' includes a front contact of each of the associated track relays.

For controlling the signals, each section. is provided with a polarized direct current relay Ythe associated track section.

of the retained neutral type having a slow pickup characteristic and designated by the reference character H with a prex the same as the reference character of the associated signal. Each relay H in-cludes an operating winding 23 and a retaining winding 24 which is inductively coupled with the operating winding and is eilective for retaining the neutral armature in its picked .up condition during pole-changing periods. Each operating winding 23 is directly connected to the associated line circuit and each retaining winding is controlled over a front contact of the track relay for the rear subsection-of For example, the retaining winding 24 of relay IOH'is ycontrolled over front contact 25 of track relay I'TR. yAs will be explained more in detail hereinafter, this feature insures a quick release `of thev relay IDH when a train Venters section IT so that a momentary improper energization of the linecircuit to the rear of location V is avoided.

For also .controlling the signals, each section is provided with a direct current neutral relay designated by the reference character J with a .prefix the same as the reference character of the associated signal. Eachrelay J isconnected to` the associated line circuit ,by a resistor, a transformer, and an Yasymmetric -unit vdesignated `by the reference characters F, M, and Q, respectively, each with a prefix `the same as the reference character lof the .associated signal.

The relatively high impedance of the relays H prevents the flow of alternating current in thesev relays .and :the transformers M prevent the ilo-w of direct .current .in .the relays J. The resistors F prevent .excessive flowlof direct current in the primary `windingsof the transformers M.

.Each section is .provided with a suitable source of direct current, here Ashown ras a battery 9, the .terminals .of vwhich are .designated by the reference vcharacters B and C, and with Ia .suitable .source of alternating current the terminals of which are designated by the reference char- ,acters yBX and CX.

-Each section is provided with `a transformer' .N having .a ,primary winding 26 directly con- .ne.cted to thealternatingcurrent terminals BX and CX and including Va secondary winding 2l.

As will :be vexplained more in detail hereinafter,

the relays H an-d J connect the secondary 4wind- "f `ings .21 .and -the directtcurrent -terminalsB and C with .the .line circuit for the section next in rear .in such a .'manner that the line .circuit is supplied with .directcurrent only of normal polarity ror with Ydirect vcurrent only -ef lreverse polarity .or with alternating current simultaneously with direct'current `of normal or reverse polarity.

For controlling the associated lamps -UE and LE, each section is provided with an approach lighting relay designated by the reference character ER .with a prefix .the .same as the reference character .of the associatedsignal. Each relay ER is connected in series with .the line circuit for the section .next in rear so that these relays-are normally fenergized and becomedeenergized only .when .the section next in Arear Vis occupied by a train. The lamps UE and LE are controlled over a back contact of the associated relay ER. For example, the lamps IDLE and IOUE are controlled by :circuits each of which includes back 4contact .28 of rrelay .IIIER so that vthese lamps are lighted only when relay IUER is released, that is, when Ythe section next in rear of location V is occupied.

Each lamp UE and LE is controlled in a similar manner by the associated relay ER for the remaining signals.

The impedance of the relays ER is of such value as to oier substantial resistance to the passage of alternating current. In order to bypass the greater portion of the alternating current, each relay ER is provided with a resistor 29 connected across the relay winding. The value of resistors 29 is so chosen that sufcient direct current will flow through the relays ER to maintain l'these relays energized when the line circuit is closed.

The relays H and J control the signal in the ffollowing manner: When relay H is deenergized (see `signal I4), the operating windings 22 of both upper and lower units U and L are in the deenergized condition so that when lamps I4UE and I4LE are lighted, the signal will display a red flight above a red light to indicate stop. When relay H is energized in the reverse direction and relay J is deenergized (see signal I3), operating winding 22 of upper unit U of that signal is energized in the reverse direction by-a circuit which lpasses from terminal B through `front contact 30 of relay I3H, back point of contact 3I of relay I3J, operating winding 22, and back point of lcontact 32 of relay J -to terminal C; and operating winding 22 of lower unit L of that signal remains deenergized, so that, when lamps I SUE and I3LE are lighted, the signal will 'display a yellow light above a red light to indicate approachnext signal 4prepared to stop. When relay H is energized in the normal direction and relay J is deenergized (see signal I2), operating winding 22 of upper unit vU of that signal is energized in the reverse direction Vover a circuit which passes from terminal B through front contact 33 of relay I2H, back point of contact 34 of relay I2J, operating winding 2v2, and back point of contact 35 of relay I2J to terminal C;

and operating Winding 22 of the lower unit L of that signal is energized in the reverse direce tion over a circuit which passes from terminal B through front contact 33 of relay I2H, normal polar contact 36-31 of relay I2H, back point of contact 38 of relay I2J, operating winding 22, and back point of contact 39 of relay I2J to terminal C so that, when lamps I2UE and I2LE .are lighted, the signal will display a yellow light above a yellowlight to indicate proceed at medium speed. When relay H is energized in the `reverse direction and relay J is energized (see signal II), operating winding 22 of upper unit U of that signal is energized in the reverse direction over a circuit which passes from terpolar contact 45-46 of relay I IH, to terminal C;

and operatingwinding 22 of lower unit L of that signal is energized in the normal direction over a circuit which passes from terminal B through front contact 40 of relay I IH, front point of co-ntact 41 of relay IIJ, operating .winding 22, and front point of contact 48 of relay IIJ to terminal C so that, when lamps IIUE and IILE are lighted, the signal will display a yellow light above a green light to indicate approach next signal at .medium speed. When the relay H is energized inthe normal direction and relay J is energized (see signal I0), operating Winding 22 of upper unit U of that signal is energized in the normal direction over a circuit which passes from terminal B through front contact 49 of relay IDH, normal polar contact 50-45 of relay IDH, front point of Contact 5I of relay IDJ, operating winding 22, front point of contact 52 of relay IDJ, and, normal polar contact 42-53 of relay IDH to terminal C; and operating winding 22 of lower unit L of that signal is energized in the normal direction over a circuit identical to that described for unit L of signal II, so that, when lamps IDUE and IDLEv are lighted, the signal will display a green light above a green light to indicate proceed at normal speed.

As shown in the drawings, the section immediately to the right of point Z is occupied by a train K so that the line circuit for the control of relays MH and I4J is opened With the result that both relays I4H and I4J are deenergized. Since relay I4H is deenergized, relay I3H is energized in the reverse direction over a circuit which passes from terminal B of battery 9 at signal I4, through resistor 29 and relay I4ER in multiple, back point of contact 54 of relay I4H, front contact 55 of relay DTR, front contact 56 of relay 1TR, operating Winding 23, front contact 51 of relay 1TR, front contact 58 of relay 8TR, and back point of Contact 59 of relay I4H to terminal C.

Since relay I3H is energized in the reverse direction and relay I3J is deenergized, relay I2H is energized in the normal direction over a circuit Which passes from terminal B of battery 9 at signal I3, through resistor 29 and relay I3ER in multiple, reverse polar contact DD-BI of relay I3H, back point of contact 62 of relay I3J, front point of contact 63 of relay I3H, front contact 64 of relay ETR, front contact 65 of relay 5TR, operating winding 23, front contact 65 of relay ETR, front contact 61 ofrelay STR, front point of contact 68 of relay I3H, back point of contact B9 of relay I3J, and reverse polar contact 1D-1I of relay I3H to terminal C.

Since relay I2H is energized in the normal direction and relay I2J is deenergized, relay IIH is energized in the reverse direction over a circuit Which passes from terminal B of battery D at signal I2, through resistor 29 and relay IZER in multiple, normal polar contact 13-14 of relay I2H, back point of contact 15 of relay I2J, front point of contact 16 of relay I2H, front contact I1 of relay 4TH., front contact 18 of relay STR, operating Winding 23, front contact 19 of relay STR, front contact 8D of relay 4TR, front point of contact 8l of relay I2H, back point of contact 82 of relay I2J, normal polar contact E I-83 of relay I2H, and secondary Winding 21 of transformer I2N to terminal C; and primary Winding 84 of transformer IIM is energized by a circuit vvhich passes from one terminal of secondary winding 21 of transformer I2N through battery 9 at signal II and thence over the saine circuit, excluding operating Winding 23 of relay I IH but including resistor I IF, as just traced for relay IIH and back to the other terminal of secondary 23. When primary Winding 84 of transformer IIM is energized, current is induced m the secondary Winding 86 so that relay IIJ is energized through asymmetric unit IIQ.

Since both relay IIH and relay IIJ are energize-d, relay IDH is energized in the normal di rection over a circuit which passes from terminal B of battery 9 at signal II, through resisto-r 29 and relay IIER in multiple, front point of contact 81 of relay IIJ, front point of contact 88 of relay IIH, front contact 89 of relay 2TH, front contact 9D of relay ITR, operating Winding 23,

front contact 9| of relay ITR, front contact 92 of relay 2TR, front point of contact 93 of relay IIH, front point of contact 94 of relay IIJ, and secondary Winding 21 of transformer I IN to terminal C; and primary Winding 84 of transformer IDM is energized by a circuit which passes from one terminal of secondary Winding 21 of transformer IIN through battery 9 at signal II, and thence over the same path, excluding operating Winding 23 of relay IDH but including resistor IDF, and thence back to the other terminal of secondary 21 of transformer IIN. Since primary Winding 84 of transformer IDM is energized, current is induced in secondary 86 of transformer IDM so that relay IDJ is energized through asymmetric unit IDQ.

Since both relays IDH and IDJ are energized, the line circuit for the section next in rear of section V--W is energized by alternating current simultaneously with direct current of normal polarity so that the signal (not shown) in the rear is caused to assume its normal proceed position. The retained neutral feature of the polarized relays H prevents tumble-down of the signal control relays to the rear. For example, when the train K vacates the section to the right of location Z so that the relay IIH is supplied with current of normal polarity to cause signal II to assume the normal proceed indication, the front points of neutral contacts 88 and 93 do not become opened during this pole-changing period so that the energy supplied to the line circuit for the section V-W is not disturbed` Consequently, the relay IDH and each succeeding .corresponding relay to the rear remains energized.

The retaining Winding 24 of each relay H is closed over a front contact of the rear track relay of the associated section so that the relays H will be comparatively quick releasing When a train is passing from a forward subsection of one track section to a rear subsection of an adjacent track section. This is done in order to avoid the signal in the rear from momentarily assuming an improper proceed position when a fast moving light engine passes from one section into another section. For example, assume that a light engine passes from subsection 2T into subsection 3T at such a speed that track relay 2TR becomes energized before track relay 3TR becomes deenergized. Under this condition, the line circuit for section V-W would be closed so that relay IDH would be energized by current o-f normal polarity until such time as relay IIH becomes released. Relay IDH, however, having a slow pickup characteristic does notl respond immediately to such energization. In the meantime track relay 3TR Will become released so that the opening of its front contact 25 will in turn open the retaining Winding 24 of relay IIH so hat this relay will release before relay IDH has had time to become energized. Signal ID, therefore, remains in a condition to display the stop indication until such time as the line circuit for the control of that signal is supplied with direct current energy in the reverse direction. Consequently, signal ID is prevented from momentarily assuming a position to display a normal proceed indication to a following train which may be occupying the section immediately in rear of the location V.

Each of the relays H functions in a similar manner to prevent tumble-do-Wn of the signal circuits to the rear and to prevent momentary impro-per indications under high speed light engine.. movements', as explained and described for signals I and Y| I.

To sum up vthus far, each signal is controlled by a direct current polarized signal control'relay and by a direct current neutral signal fcontrol relay. The polarized relay is directly connected to a line circuit and the neutral relay is connected to the line circuit through a transformer and .asymmetric 1unitso that the neutral relay will be energizedonly when the line circuit is supplied Withalternating current. The line circuit '1s controlled by the track relays of the section-with which the signal is vassociated and by the signal control relays for vthe signal next in advance. When the polarized relay is deenergized,V the associated signal is in the condition to'indicate stop and the line circuit tothe rear is supplied with direct current only of reverse polarity. When the polarized relay alone is energized in the reversedirection, the associated signal is in condition .toindicate prepare to stop `at ,next signal and the line circuit to the rear .is supplied with direct current only of normal polarity. When the polarized relayV alone is energized in the :normal direction, the associated signal is in condition to indicate proceed at medium speed and the line circuit to the rear is supplied with alternating current aswell as with direct current `of reverse polarity. When the polarized relay isenergized in the reverse direction and the neutral relay also is energized, the associated signal is in condition to indicate approach next signal at medium speed andthe line circuit A'to the rear is supplied with alternating current'as wellras with direct current .of normal polarity. When the polarized relay is energized in the normal direction and the neutral relay iszenergized, the associated signal is in condition to indicate proceed at normal speed and the line circuit to the rear is supplied with alternating current as well as with direct current of normal polarity. The signaling scheme illustrated in Figs. 1A, 1B, and 1C, therefore, provides a distinctive control for each of four sections in the rear of an occupied section whereby the Wayside signals are-caused to-.proVideLa four-block, fiveindication, signal system.

Referring next to Figs. 2A and 2B, the system illustrated herein provides a four-indication, three-block, system of signaling.

Each signal includes an upper unit U and lamp E which functions in a manner identical to that described for the searchlight mechanisms shown in Figs. 1A, 1B, andlC. Each signal also includes a lower unit LA which is here shown as a single yellow lamp Y.

For controlling the signals, each section is-provided with the usual polarized direct current relay H and with the usual neutral direct current relay J. The relays H and J are connected to 'the associated line circuit in the same manner as described for the system shown in Figs. 1A, flB, and .1C.

For controlling the lamps E and Y, each section Vis provided with the usual approach lighting relay ER which is connected, in multiple with the resistor 29, in series with the line circuit for thesection next in rear.

Each .section is provided `with the usual battery 9 and with the usual source of alternating current.

Each section is also provided with the usual transformer N having its primary winding 26 connected to the terminals BX and CX of the source of alternating current energy and having its secondary winding21, at times, connected in series with the line circuit forthe section next in rear.

The relays Hfand J control the upper units U andthe lower Vunits LA in the following manner: When the relay H isdeenergized (see signal I3), both upper and lower units are deenergizedso that, when lamp 3E is lighted, the signal will display a single red light to indicate stop. When the relay'H is energizedin the reverse direction y(see signal l2), operating winding 22 of upper unit U of that signal is energized in the reverse direction bya circuit which passes from terminal B through reverse polar contact95 96 of relay I2H, operating winding '2.2, .and front contact 91 aswell as normal contact 98-99 both of relay I2H to terminal C, so that, when lamp |.2E isY lighted, the signal will display a single yellow light to indicate approach next signal prepared to stop. When relay H is energized in the normal direction and relay J is deenergized (see signal II), operating winding 22 of upper unit U of that signal is energized `in the reversedirection over a circuit which passes from terminal B through back point of contact |00 of relay HJ, normal polar contact IUI-96 of relay H, operating winding 22, front Vcontact |'02'of relay H, normal polar contact 98|03 of relay ||H,and back point of-contact |04 of relay IIJ; and a circuit isestablished for lamp 'Y kof lower unit LA which includes back contact |05 of relay :l 5J and front contact |06 as well as normal polar contact lOl- |08 both of relay ||H so that when back contact 28 of relayll IER becomes closed, the signal will display a yellow light above a yellow light to indicate approach next signal at medium speed.

When relay H is energized in the normal direction and relay J is energized (see signal I0), operating winding 22 of upper unit U of that signal is Venergized in the normal Adirection over a circuit which passes from terminal B through front point of contact |09 of. relay |0J, normal polar contact H13- 98 as well as front contact I I0 both of relay |0H, operating winding 22, normal polar contact 96|0I of relay I2H, and front point of contact III of relay I2J so that, when lamp 0E 'is lighted, the signal will display a single green light to indicate proceed at normal speed.

As .shown in the drawings, thelsection immediately to the right of location Y is occupied by a train K so that the line circuit for the control of relay I3H and 3J is opened. Consequently, both relays are deenergized. Y

When relay I3H is deenergized, relay I2H is supplied with energy in the reverse direction over -a circuit which passes from terminal B of battery 9 at signal I3, through relay I3ER and resistor 29 in multiple, back point of contact ||2 of relay I3H, front contact ||3 of relay GTR, front contact |I4 of relay STR, operating winding 23, front contact `I I5 of relay STR, front contact ||6 of relay GTR, and .backY point of contact I|`| of relay I3H to terminal C.

When relay I2H is energized in the reverse direction, relay ||H is-energized in the normal direction over a circuit which passes from terminal B of battery 9 at signal I2, through relay |2ER and resistor 29 in multiple, front point of contact |,|8 of relay I2H, front contact |I9 of relay 4TH., front contact |20 of relay 3TH., operating winding 23, front contact |2`| of Arelay3fI'R., front contact |22 of relay 4TR, front point of contact |23 of relay |2H, and reverse polar contact |24|25 of relay |2H to terminal C.

When relay IH is energized in the normal direction, relay lUH is energized in the normal direction over a circuit which passes from terminal B of battery 9 at signal through relay HER and resistor 23 in multiple, front point of contact |26 of relay HH, front contact |21 of relay 2TH, front contact |28 of relay ITR, operating winding 23, front contact |29 of relay lTR, front contact |33 of relay 2TH, front point of contact l3| of relay IIH, normal polar contact |24-i32 of relay ||H and .secondary winding 2l of transformer IEN to terminal C; and primary winding 33 of transformer lllM is energized by a circuit which passes from one terminal of secondary Winding 2l of transformer llN, through battery 9 at signal relay HER and resistor 29 in multiple, front point of contact |28:` of relay HH, front contact |27 of relay ZTR, front contact |23 of relay ITR, resistor iElF, primary winding 84, front contact |23 of relay |TR, front contact |33 of relay ETR., front point of contact |3| of relay i lH, and normal polar contact |24|32 of relay ill-i to the other terminal of secondary Winding 2'?. When primary winding 84 of transformer isili/i is energized, current is induced in secondary winding B6 so that relay IOJ is energized by direct current through .asymmetric unit WQ.

When relay |H is energized in the normal direction, the line circuit for the section immediately in rear of location V is supplied with alternating current simultaneously with direct current of normal polarity so that the signal (not shown) to the rear will be in a condition for displaying the normal proceed indication.

The retained neutral relays H function to prevent tumble-down of the signal control circuits to the rear during pole-changing periods and to prevent momentary improper proceed indications during the passage of high speed light engines from one section to another, in a manner identical to that described for the system shown in Figs. iA, 1B, and 1C.

To sum up for the system illustrated in Figs. 2A and 2B, each signal is controlled by a polarized direct current relay directly connected to a line circuit and by a neutral relay connected to the line circuit through a transformer `and an asymmetric unit. The line circuit is governed by the track relays for the section with which the signal is associated and by the polarized signal control relay of the signal next in advance. When the polarized relay is deenergized, the associated signal is in condition to indicate stop and the line circuit in the rear is supplied with direct current only of reverse polarity. When the polarized relay is energized in the reverse direction, the associated signal is in condition to indicate approach next signal prepared to stop and the line circuit in the rear is supplied with direct current only of normal polarity. l/Vhen the polarized relay is energized in the normal direction and the neutral relay is deenergized, the associated signal is in condition to indicate approach next signal at medium speed and the line circuit in the rear is supplied with alternating current as well as. with direct current of normal polarity. When the polarized relay is energized in the normal direction and the neutral relay also is energized, the associated signal is in condition to indicate proceed at normal speed and the line circuit to the rear is supplied with alternating current as well as with direct current of normal polarity. The signaling system illustrated in Figs. 2A and 2B, therefore, provides a distinctive control for each of these sections in the rear of an occupied section whereby the wayside signals are caused to provide a three-block, four-indication, signal system.

Referring now to Fig. 3, the reference character A with a prefix the same as the reference character of the associated signal designates an alternator which may be substituted at each signai for the usual source of alternating current the terminals of which were designated inthe preceding drawings by the reference characters BX and CX.

as here shown, the alternator A is of the wellkncwn tuned reed type. The reference character |34 designates .an elastic reed which is caused to vibrate between terminals |35 and |36 by a control winding |31. In the deenergized condition, reed |34 does not connect with either terminal |35 or l36 but does connect with a terminal |38. When energy is supplied to the alternator A, winding |31 will attract reed |34 causing it to connect with terminal |36 and to move .away from terminal |38, causing winding |3l to become deenergized. Upon deenergization of winding |32', the resilience of reed |34 will cause it to move away from terminal |36 and to connect with terminal |35 as Well as with terminal |38. The circuit for winding |31 being then again completed through terminal |38, winding |371' will again attract reed |34 causing the cycle of operation just described to be repeatedly energized and deenergized as long as energy is supplied to its control circuit.

When reed |34 connects with terminal |36, current is supplied to the right-hand portion of the primary winding |39 of transformer NA; and when reed |35 connects with terminal |35, current is supplied in the opposite direction to the lefthand portion of primary winding |39. Alternating current, therefore, will be induced in the secondary winding |36 of transformer NA. The secondary winding |46 is connected in series with the line circuit for the section next in rear whenever the relay H is energized in the normal direction in a manner the same as described for secondary winding 2l of transformer N shown in Figs. 2A and 2B.

It will be noted that the operating winding 23 of relay H is not provided with a slow pickup characteristic and that the retaining winding 24 of relay H is not controlled over a front Contact of the rear track relay. It is understood, of course, that such control may be provided if it is desired to prevent possible undesirable signal indications under high speed light engine movements. Otherwise, the relay H and the relay J control the associated signal and the line circuit for the section next in rear in exactly the same manner as described for the system shown in Figs. 2A and 2B.

That is, when relay H is deenergized, the associated signal will be in condition to display the stop indication and the line circuit in rear will be supplied with direct current only of reverse polarity. When the relay H alone is energized in the reverse direction, the associated signal will be in condition to indicate prepare to stop at next signa and the line circuit in rear will be supplied with direct current only of normal polarity. When the relay H alone is energized in the normal direction, the associated signal will be in condition to indicate approach next signal at medium speed and the line circuit in rear will be supplied with alternating current simultaneously with direct current of normal polarity.

' When `the relay H is energized in the normal directiori and the relay J also is energized, the associated signal will be in condition to indicate proceed at normal'speed and the line circuit V in rear will be supplied with alternating current Vcircuits and apparatus which may be used when .a polarized relay HA of the ordinary type is substituted for the polarized relay H having the retained neutral feature. The slow-releasing repeating relay HP is provided for the control of the line circuit for the section next in rear so that, during pole-changing periods, when the relay HA releases momentarily, the relay HP will maintain its frontV contacts closed Vto provide uninterrupted energization of the line circuit to the Therelay HP is provided with two pickup circuits. One circuit passes from terminal B through front contact |42 of relay HA, signal contact |43|44 closed when the signal is in the clearindication position and relay HP to terminal C. The othercircuit passes from terminal B through Yfront contact |42 of relay HA, signal contact |43,-

|45 closed when the signal is in the stop and caution position, signal contact Mii- |41 closed when Y. the signalis in the caution position, and relay HP to terminal C. That is, relay HP "is Yenergized whenever relay HA is energized provided theV upper mechanism U of the associated signal isY in the clear or caution position.

Contactsk |48 and |49 of relay HP and normal relay HAl control the current supplied to theline Y circuit for the section .next in rear in a manner similar to that described for the relay HA shown inFigs. 2A and 2B. That is, when the relay HP is deenergized, the line circuit in rear is suppliedV HA is energized in the reverse direction, the lineV circuit in rear is supplied with direct current only of normal polarity; whereas when the relay HP is energized and the Vrelay HA is energized in the normal direction, secondary winding 21 of transformer N is connected in series with the line circuit in rear so that alternating current is supplied to such line circuitsimultaneously with direct current of normal polarity.

The relays HA and'J control the associated signal in a manner similar to that described for the relays H and J shown in Figs. 2A and 2B. That is, when the relay HA is deenergized, the signal is in condition to display the stop indication. When the relay HA alone is energized in theV reverse direction, theV signal is in condition to indicate approach Vnext signal prepared to stop. When the relay HA alone is energized in the normal direction, the signal isin condition to indicate approach next signal at` medium speed. When the relay HA is energized in the normal direction and the relay J also is energized, `the signal is in condition to indicate proceed at normalY speed. Y

It will be noted that operating winding 22 of upper mechanism U is provided with a branch circuit around front contact '|54' of relay H which circuit includes front contact |53 of relay HP. This branch path Yremains closed during polechanging periods when front contact |54 of relay HA becomes momentarily opened and thereby reduces the period of time during which windingV 22 of mechanism U is without energy sincerwithY Referring now to Fig. 5, I have illustratedY herein a scheme for connecting the secondary Winding 2l of transformer N in multiple with the line circuit for the section next in rear instead-of inV series as illustrated in the preceding figures. As here shown, secondary winding 2l is connected by means of` a resistor |58 across the line circuit between the contacts of the relay H and the approach lighting relay ER. The resistor |58 prevents excessive ilow of direct current from `the battery 9 in the secondary winding 21 andV the reactor |59 prevents excessive flowof alternating current through the relay EP and the battery 9.

` The primary winding 26 of transformer N is connected with the terminals BX and CX of the alternating current source of energy over front contact |55 and normal polar contact ISS- |51 both of relay H. It will be readily apparent that when relay H is energized in the normal direction, alternating current Will be supplied simultaneously with direct current of normal polarity to the line circuit for the section next in rear. It will be apparent also that this modification may be applied to any of the signal systems described in the preceding figures.

Although I have herein shown and described several forms ofV apparatus embodying my invention, it is understood that various changes and modifications may be made therein Withinthe scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is: n

1. In combination, a section `oi" railway track, a line circuit for said section, track circuit means for said section for governing said line circuit, means controlled by traffic conditions in advance of said section for supplying said line circuit with direct current only of one polarity or with direct current only of the other polarity or with alternating current simultaneously with direct current of said one polarity, and signaling means for said section controlled by said line circuit and selectively responsive to the character and number of currents with which such line circuit is supplied.

2. In combination, a section of railway track, a line circuit for said section, track circuit means for said section for governing said line circuit, means controlled by traffic conditions in advance of'said section for supplying said line circuit with direct current only of one polarity or with direct Vcurrent only of the other polarity or with alternating current simultaneously withV direct current of said one polarity'or with alternating current simultaneously withY direct current of the other polarity, and signaling means for said section governed by said line circuit and selectively responsive to the character and number of currents with which such line circuit is supplied. 3. In combination, a section of railway track having a track circuit including a track relay, a line circuit for said section including a pair of line wires each including a front contact of said track relay, a polarized direct current line relay connected to said line circuit, a direct current neutral line relay, means including an asymmetric unit for connecting said neutral relay to said line circuit, a signal for said section controlled by said two line relays, and means governed by traffic conditions in advance of said section for supplying said line circuit with direct current only of one polarity or with direct current only of the other polarity or with alternating current simultaneously with direct current of said one polarity.

4. In combination, a section of railway track having a track circuit including a track relay, a line circuit for said section governed by the associated track relay, means governed by traic conditions in advance of said section for supplying said line circuit with direct current only or with alternating current simultaneously with direct current, a direct current line relay connected to said line circuit, another direct current line relay receiving energy from said line circuit through an asymmetric unit, and a signal for said section governed by said two line relays.

5. In combination, a section of railway track having a track circuit including a track relay, a line circuit for said section governed by the associated track relay, means governed by traffic conditions in advance of said section for supplying said line circuit with direct current only or with alternating current simultaneously with direct current, a direct current line relay connected to said line circuit, another direct current line relay receiving energy from said line circuit through an asymmetric unit, and a signal for said section capable of displaying several distinctive aspects having varying degrees of speed restrictions and governed by said two line relays in such a manner that said signal will display its least restrictive aspect only if said two line relays are energized simultaneously.

6. In combination, a section of railway track having a track circuit including a track relay, a line circuit for said section including a pair of line wires each including a front contact of said track relay, a polarized direct current line relay connected to said line circuit, a direct current neutral line relay, means including an asymmetric unit for connecting said neutral relay to said line circuit, means governed by traic conditions in advance of said section for supplying said line circuit with direct current only of one polarity or with direct current only of the other polarity or with alternating current simultaneously with direct current of said one polarity or with alternating current simultaneously with direct current of said other polarity, and a signal for said section capable of displaying several distinctive aspects having varying degrees of speed restrictions and governed by said two line relays in such a manner that said signal will display its two least restrictive aspects only if said two line relays are energized simultaneously.

'7. In combination, a section or" railway track having a source of current connected across the rails at one end of the section and a track relay connected across the rails at the other end of the section, a line circuit for said section including a pair of line wires each governed by a front contact of the associated track relay, a direct current relay connected to said line circuit, another direct current relay, means including an' asymmetric unit and a transformer as well as a resistor for connecting said other relay to said line circuit, means governed by trarc conditions in advance of said section for supplying said line circuit with direct current only or with alternating Acurrent simultaneously with direct current, and a signal for said section governed by said two direct current relays.

8. A railway signal system comprising a stretch of railway track divided into a plurality of successive sections, a line circuit for each section each including a pair of line wires, track circuit means for each section for governing the associated line circuit, a direct current polarized line relay for each section connected to the associated line circuit, a direct current neutral line relay for each section receiving4 energy from the associated line circuit through an asymmetric unit, a source of direct current energy for each section, means for each section governed by the associated polarized line relay for supplying the line circuit for the section next in rear with current of one polarity or the other polarity from the associated source of direct current according as said polarized line relay is energized or deenergized respectively, a source of alternating current energy for each section, a transformer for each section having a primary winding and a secondary winding, said primary winding connected to its associated source of alternating current, means for each section' for connecting the secondary of the associated transformer in series with said line circuit next in rear eiective when the associated polarized relay is energized by current of said one polarity, and traic governing means for each section controlled by both the associated line relays.

9. A railway signal system comprising a stretch oi railway track divided into a plurality of successive sections, a line circuit for each section each including a pair of line wires, track circuit means for each section for governing the associated line circuit, a direct current pol-arized line relay for each section connected to the associated line circuit, a direct current neutral line relay for each section receiving energy from the associated line circuit through an asymmetric unit, a source of direct current energy for each section, means for each section governed by the associated polarized line relay for supplying the line circuit for the section next in rear with current of one polarity or with current of the other polarity from the associated source of direct current according as said polarized line relay is energized or deenergized respectively, a source of alternating current energy for each section, a transformer for each section having a primary winding and a secondary winding, said secondary winding connected in multiple with the associated source oi direct current, means for each section for connecting the primary winding of the associated transformer to the associated source of alternating current effective when the associated polarized relay is energized by current of said one polarity, and trac governing means for each section controlled by the two associated line relays.

10. A railway signal system comprising a stretch of railway track divided into a plurality of successive sections, a line circuit for each section each including a pair of line wires, track circuit means for each section for governing the associated line circuit, a direct current polarized line relay for each-section connected tothe associated line circuit, a direct current neutral line relaylfor each section receiving energy from the associated line circuit through an asymmetric unit, `a source Y oi direct curientenergy for each section, Vmeans for each section governed bythe associatedzpolarized line relay for supplying the line circuit for the-section next inrear withl current of one polarity or withcurrent of the other polarity from the associated source of direct current accordingV as said polarized line relay isenergized or deenergized respectively, a source of alternating current energy for each section, a transformer foreach section having a primary winding and a secondary winding, said primary winding connected to the associated source of alternating current, means for each section including` a front neutral contact of the associated `polarized relay and a polar Vcontact closed when such relay is energized by currentofsaid one polarity for connecting the secondary of the associated transformer in series with said line circuit next in rear, and trailic governing meansfor each section controlled by said two associated line relays.

Vl1. In combination, a pluralitytofV successive sections of railway track, a line circuit for each section 'each' including a pair of line Wires, track circuit means for each section for governing the associated line circuit, a direct current polarized line relay for each section connected to thek associated line circuit, a direct current neutral line relay for each section receiving energy from the associated section through'an asymmetricrunit,

t means for each-section for supplying direct current only of normal or of reverse polarity to the line circuit fortheV section next in rear according as ythe associated 'polarizedV relay is'energized or deenergized respectively, means for each section for supplying alternating current simultaneously with direct current Yof normal polarity to such line circuit next in rear when the associated polar- Y ized relay is energized by current of normal polarity, an auxiliary relay for each` section connected in series with such line circuit next in rear, and a Vsignal for each section controlled by said two associated relays and saidl associated auxiliary relay.

l2. In combination, a plurality of successive sections of railway track, a line circuit for each section each including a pair of line wires, track circuit means for each section for governing the associated line circuit, a direct current polarized line relay for each section connected to the associated line circuit,'a direct current neutral line relay for each section receiving energy `from the associated section through an asymmetric unit,

meansrfor each section for supplying direct current only of normal or of reverse polarityto the line circuit for the section next in rear according as the associated polarized relayris energized or deenergizedY respectively, means foreach section for supplying'alternating current simultaneously with direct current of normal polarity to such line circuit next in rear when the associated polarized relay is energized by current of normal polarity, an auxiliary relay for each section con- Y nectedV in series With such line circuit next in rear, a resistorconnected around each said auxil iary relay, and a signal for each section controlled by said two associated line relays and by-said associated auxiliary relay.

i3'. In combination, a'plurality of successive sections of railway track, a lline circuit for eachV section each including a pair of line wires, track circuit Vmeans for each section forgoverning the associated -line circuit, a directc'uirent polarized line relay for each section connected to the associated line circuit, a direct current neutral line relay for each section receiving Aenergy from the Y associated section through an asymmetric unit,

vmeans for each section ,for supplying direct cur'- Vlo for supplying 4alternating current simultaneously with Y:direct current of lnormal polarity to such line circuit next in rear when the associated polarized relay is energized by current of normal polarity, an approach Vlighting relay for each section connected in series with such line circuit in-rear, a signal for each section governed by said `tvvo associated line relays, and a lamp for each signal governed by the associated, approach lighting relay. Y n

14. In combination, a plurality of ysuccessive sections of railway track, a line circuit for each section each including a pair of line wires, track circuitV means for each section for governing the associated .line circuit, a direct current polarized line relay for each section connected to the associated line circuit, a direct current neutral line relay for each section receiving energy Vfrom the associated section through an asymmetric unit, means for `each'section for supplying direct current -only of normal or of reverse polarity to the line circuit for'the section 'next in rear according as the associated polarized relay is energized or deenergized respectively, meansY for each section for supplying alternating current simultaneously with direct current of normal polarity to suchlinecircuit next in rear when` the Vassociated polarized relay is energized by,V

current of normal polarity, an approach lighting relay for each section connected inlseries Ywith such line circuit next in rear, and a signal mechanism including a lamp for each section, said signal mechanism controlled by contacts ofV said two associated line relays and said lamp controlled by a contact of said associated approach lighting relay. v

l5. A railway signaling system comprising a plurality of successive sections of railway track, a line circuit for each section, track circuit means for each section for governing the associated line circuit, a first direct current line relay for each section connected to the associated line circuit, a second direct current line relay for each section, means including an asymmetric unit for connecting said second relayto the associated line circuit, means governed by traino conditions in advance-of said section for supplying the line circuit for the section next in rearV with direct current only or with alternating current simultaneously with direct current, an approach lighting relay for each section connected in series with such line circuit next in rear, and a signal for each section governed by said two'associated line relays as Well as by the associated approach light- Y ingv relay.

16. .In a signaling system forV a railway track divided intosections,a polarized direct current relay for each section having polar and neutral contacts, a neutral direct current relay for each section connected to an asymmetric unit, signals'for each section controlled by neutral and polar contacts of the associated polarized relay and by contacts of the associated neutral relay, means for each section including neutral and polar'contacts of the associated vpolarized 'relay for supplying direct current only of normal or reverse polarity to the corresponding polarized relay or the section next in rear according as said rst mentioned relay is energized or deenergized respectively and for supplying alternating current to the asymmetric unit associated with the neutral relay of the section nekt in rear when said first mentiohed polarized relay is energized in the normal direction, means for each polarized relay eiective for normally rendering the neutral contacts of such polarized relay slow acting, track circuit means for each section for controlling the associated polarized and neutral relays and for at times disabling the slow-acting means of the associated polarized relay.

17. In a signaling system for a railway track divided into sections, a polarized direct current relay for each section having polar and neutral contacts, a neutral direct current relay for each section connected to an asymmetric unit, signals for each section controlled by neutral and polar contacts of the associated polarized relay and 'by contacts of the associated neutral relay, means for each section including neutral and polar contacts of the associated polarized relay for supplying direct current only of normal or reverse polarity to the corresponding polarized relayof the section next in rear according as said first mentioned relay is energized or deenergized respectively, and for supplying alternating current to the asymmetric unit associated with the neutral relay of the section next in rear when said first mentioned polarized relay is energized in the normal direction, means for each polarized relay effective for normally rendering the neutral contacts of such polarized relay slow acting, track circuit means for each section including a forward track relay and a rear trackrrelay, means for each section including both the forward and the rear track relays for controlling the associated polarized and neutral relays, and means for each section including the rear track relay of such section for disabling the slow-acting means of the associated polarized relay when said rear track relay is released.

18, In a signaling system for a railway track divided into sections, a polarized direct current relay for each section having polar and neutral contacts, a neutral direct current relay for each section connected to an asymmetric unit, signals for each section controlled by neutral and polar contacts of the associated polarized relay and by contacts of the associated neutral relay, means for each section including neutral and polar contacts of the associated polarized relay for supplying direct current only of normal or reverse polarity to the corresponding polarized relay of the section next in rear according as said rst mentioned relay is energized or deenergized respectively and for supplying alternating current to the asymmetric unit associated with the neutral relay of the section next in rear when said first mentioned polarized relay is energized in the normal direction, means for each polarized relay effective for normally rendering the neutral contacts of such polarized relay slow acting, track circuit means for each section including a forward track relay and a rear track relay, means for each section including both the forward and the rear track relays for controlling the associated polarized and neutral relays, and means for each section including a front contact of the rear track relay associated therewith for rendering said slow-acting means of the associated polarized relay ineffective` 19. In combination, a section of railway track having a track circuit including a track relay, a line circuit for said section including a front contact of said track relay, means governed by tramo conditions in advance of said section for supplying said line circuit with direct current only of normal polarity or with direct current only of reverse polarity or with alternating current simultaneously with direct current of normal polarity or with alternating current simultaneously with direct current or reverse polarity.

a direct current polarized line relay connected to said line circuit, a direct'current neutral'line relay, means including an asymmetric unit for connecting said neutral relay to said line circuit, and a signal for said section controlled by neutral and polar contacts of said polarized relay and by contacts of said neutral relay.

20. In combination, a section of railway track having a track circuit including a track relay, a line circuit for said section including a front contact of said track relay, means governed by traffic conditions in advance of said section for supplying said line circuit with direct current only of normal polarity or with direct current only of reverse polarity or with alternating current simultaneously with direct current of normal polarity or with alternating current simultaneously with direct current or reverse polarity, a

direct current polarized line relay connected to said line circuit, a direct current neutral line relay, means including an asymmetric unit for connecting said neutral relay to said line circuit,

a signal for said section including a rst mechanism and a second mechanism each selectively responsive to the polarity of the current supplied thereto, and means including contacts of both line relays for reversibly governing both said mechanisms.

21. In combination, a section of railway track having a track circuit including a track relay, a line circuit for said section including a front contact of said track relay, means governed by traiic conditions in advance of said section for supplyl ing said line circuit with direct current only oi' normal polarity or with direct current only of reverse polarity or with alternating current simultaneously with direct current of normal polarity or with alternating currentI simultaneously with direct current ofreverse polarity, a direct current polarized line relay connected to said line circuit, a direct current neutral line relay, means including an asymmetric unit for connecting said neutral relay to said circuit, a signal for said section including a iirst mechanism and a second mechanism, a first circuit for said rst mechanism including a pair of front contacts of said neutral relay and a pair of normal polar contacts of said polarized relay as well as a front Contact of said polarized relay, a second circuit for said first mechanism including a pair of front contacts of said neutral relay and a pair oi' reverse polar contacts or said polarized relay as well as a front neutral contact of said polarized relay, a third circuit for said iirst mechanism including a pair of back contacts of said neutral relay and a pair of normal polar contacts of said polarized relay as well as a front Contact of said polarized relay, a fourth circuit for said rst mechanism including a pair of back contacts of said neutral relay and a pair of reverse polar contacts of said polarized relay as well as a front contact of said polarized relay, a first circuit for said second mechanism including a pair of iront contacts of said neutral relay and a front contact of said polarized relay, .and a second circuit for said seco-nd mechanism including a pair of back contacts of said neutral relay and a normal polar contact as well as a front neutral contact of said polarized relay.

22. In combination, a section ci railwayY track having a track circuit including a track relay, a line circuit for said section including a front contact of said track relay, means governed by traffic conditions in advance of said section i'or supplying said line circuit with direct current only of normal polarity or with direct current only of reverse polarity or with alternating current simultaneously with direct current of normal polarity or with alternating current simultaneously with direct current of reverse polarity, a direct current polarized line relay connected to said line circuit, a direct current neutral line relay, means including an asymmetric unit for connecting said neutral relay to said line circuit, and a signal for said section controlled by said two line relays and arranged to have a rst aspect when said polarized relay is deenergized, a second aspect when said neutral relay is deenergized and said polarized relay is energized reverse, a third aspect when said neutral relay is deenergized and said polarized relay is energized normal, a fourth aspect when said neutral relay is energized and said polarized relay is energized reverse, and a fifth aspect when said neutral relay is energized and said polarized relay is energized normal.

23. In combination, a section of railway track having a track circuit including a track relay, a line circuit for said section including a front Contact of said track relay, means governed by traiiic conditions in advance of said section for supplying said line circuit with direct current only ofY normal polarity or with direct current only of reverse polarity or with alternating current simultaneously with direct current of said one polarity, a direct current polarized line relay connected to said line circuit, a direct current neutral relay, means including an asymmetric unit for connecting said neutral relay to said line circuit, a signal for said section including a rst indication unit comprising a mechanism and a second indication unit comprising a lamp, a first circuit for said mechanism including a front contact and a normal polar contact of said polarized relay as well as a front contact of said neutral relay, a second circuit for said mechanism including a front contact and a normal polar contact of said polarized relay as well as a back contact of said neutral relay, a third circuit for said mechanism including a front contact and a reverse polar contact of said polarized relay as well as a back contactof said neutral relay, and a circuit for said lamp including a front contact and a normal polar contact of said polarized relay as well as a back Contact of said neutral relay.

24. In combination, a section of railway track having a track circuit including a track relay, a line circuit for said section including a front contact of said track relay, means governed by traic conditions in advance of said section for supplying said line circuit with direct current only of normal polarity or with direct current only of reverse polarity or with alternating current simultaneously with direct current of normal polarity, a direct current polarized line relay connected to said line circuit, a direct current neutral relay, means including an asymmetric unit for connecting said neutral relay to said line circuit, a signal for said section including a first indication unit comprising a mechanism and a second indication unit comprising .a lamp, contacts operably governed by said signal, a slow-acting repeating relay governed by said contacts and by said polarized relay, energizing circuits for said mechanism and said lamp including contacts of both said polarized and said neutral relays, anda branch circuit for said mechanism including a contact of said repeating relay.

25. A railway signal system comprising a plurality of successive sections of railway track each having a track circuit including a track relay, a line circuit for each section governed by the associated track relay, a polarized direct current relay for each section connected to the associated line circuit, a neutral direct current relay for each section, means including an asymmetric unit for connecting each neutral relay to the associated line circuit, a signal for each section governed by the associated polarized relay and by the associated neutral relay, contacts for each section operably governed by the associated signal, a repeating relay for each section governed by the associated contacts and by the associated polarized relay, means for each section for supplying the line circuit for the section next in rear with direct current only of reverse polarity when said repeating relay is deenergized and for supplying such rear line circuit with direct current only of normal polarity when said repeating relay is energized and said polarized relay is energized reverseas well as for supplying such rear line circuit with alternating current simultaneously with direct current of normal polarity when said repeating relay is energized and said polarized relay is energized normal.

26. A railway signal system comprising a plurality of successive sections of railway track each having a track circuit including a track relay, a line circuit for each section governed by the associated track relay, a polarized direct current relay for each section connected to the associated line circuit, a neutral direct current relay for each section, means including an asymmetric unit for connecting each neutral relay to the associated line circuit, a signal for each section governed by the associated polarized relay and by the associated neutral relay, contacts for each section operably governed by the associated signal, means for each section including a back contact of said polarized relay for supplying direct current only of reverse polarity to the line circuit for the section next in rear, means for each section including a front contact and a reverse polar contact of said polarized relay for supplying direct current only of normal polarity to such rear line circuit, and means for each section including a front contact and a normal polar contact of said polarized relay for supplying alternating current simultaneously with direct current of normal polarity to such rear line circuit.

27. A railway signal system comprising a plurality of successive sections of railway track each having a track circuit including a track relay, a line circuit for each section governed by the associated track relay, a polarized direct current relay for each section connected to the associated line circuit, a neutral direct current relay for each section, means including an asymmetric unit for connecting each neutral relay to the associated line circuit, a signal for each section governed by the associated polarized relay and by the associated neutral relay, contacts for each section operably governed by the associated signal, means for each section including a back cone tact of said polarized relay for supplying direct current only of reverse polarity to the line circuit for the section next in rear, means including a front contact and a reverse polar contact of said polarized relay as well as a back contact of said neutral relay for supplying such rear line circuit with direct current only of normal polarity, means including a front contact and a normal polar contact of said polarized relay as well as a back contact of said neutral relay for supplying alternating current simultaneously with direct current of reverse polarity to such rear line circuit, and means including a front contact of said polarized relay and a front contact of said neutral relay for supplying alternating current simultaneously with direct current of normal polarity to such rear line circuit.

28. A railway signal system comprising; a first, a second, a third, and a fourth track section over which traic normally progresses in the order named, a line circuit for each section including a pair of line wires, track circuit means for each section for governing the associated line circuit, a polarized direct current relay for each section connected to the associated line circuit, a neutral direct current relay for each section receiving energy from the associated line circuit through an asymmetric unit, a signal for each section governed by the associated polarized and neutral relays, means eiective when the fourth section is occupied to supply the line circuit for the third section with direct current Only of reverse polarity, means then effective to supply the line circuit for the second section with direct current only of normal polarity, and means then effective to supply the line circuit for the iirst section with alternating current simultaneously with direct current of normal polarity.

29. A railway signal system comprising a first, a second, a third, a fourth, and a fifth track section over which traflic normally progresses in the order named, a line circuit for each section including a pair of line wires, track circuit means for each section for -governing the associated line circuit, a polarized direct current relay for each section connected to the associated line circuit, a neutral direct current relay for each section receiving energy from the associated line circuit through an asymmetric unit, a signal for each section governed jointly by the associated polarized and neutral relays, means effective when the fifth section is occupied to supply the line circuit for the fourth section with direct current only of reverse polarity, means then effective to supply the line circuit for the third section with direct current only of normal polarity, means then effective to supply the line circuit for the second section with alternating current simultaneously with direct current of reverse polarity, and means then effective to supply the line circuit for the first section with alternating current simultaneously with direct current of normal polarity.

30. A railway signal system comprising a plurality of successive sections of railway track each having a track circuit including a track relay, a line circuit for each section governed by the associated track relay, means effective when one section is occupied to supply the line circuit for the section first in rear of such occupied section with current of one character, means then effective to supply the line circuit for the section second in rear of such occupied section with current of another character, means then effective to supply the line circuit for the section third in rear of such occupied section with current of still a diiferent character simultaneously with current of said other character, and signaling means for each section governed by the associated line circuit and selectively responsive to the character and number of the currents with which such line circuit is supplied.

3l. A railway signal system comprising a plurality of successive sections of railway track each having a track circuit including a track relay, a line circuit for each section governed by the associated track relay, means eiective when one section is occupied to supply the line circuit for the section iirst in rear of such occupied section with currrent of one character, means then effective to supply the line circuit for the section second in rear of such occupied section with current of another character, means then effective to supply the line circuit for the section third in rear of such occupied section with current of still a diiTerent character simultaneously with current of said other character, means then effective to supply the line circuit for the section fourth in rear of such occupied section with said current of a different character as well as with current of said one character, and signaling means for each section governed by the associated line circuit and selectively responsive to the character and number of the currents with which such line circuit is supplied.

32. In combination, a section of railway track having a track circuit including a track relay, a line circuit for said section including a pair of line wires each including a front contact of said track relay, a polarized direct current line relay connected to said line circuit, a direct current neutral line relay, means including an asymmetric unit for connecting said neutral relay to said line circuit, a signal for said section controlled by said two line relays, and means including an alternator and governed by traffic conditions in advance of said section for supplying said line circuit with direct current only of one polarity or with direct current only of the other polarity or with alternating current simultaneously with direct current of said one polarity or with alternating current simultaneously with direct current of said other polarity.

33. A railway signal system comprising a stretch of railway track divided into a plurality of successive sections, a line circuit for each section including a pair of line wires, track circuit means for each section for governing the associated line circuit, a direct current polarized line relay for each section connected to the associated line circuit, a direct current neutral relay for each section receiving energy `from the associated line circuit through an asymmetric unit, a source of direct current energy for each section, means for each section for supplying the line circuit for the section next in rear with current of one polarity or with current of the other polarity from the associated source of direct current according as the associated polarized relay is energized or deenergized respectively, a source of alternating current including a tuned reed alternator for each section, means for each section for supplying said line circuit next in rear with alternating current effective when the associated polarized relay is energized by current of said one polarity, and traffic governing means for each section governed by the two associated line relays.

RALPH R. KEMMERER.

toy 

